7 Mendel came to understand….Plant progeny (offspring) did not show blending of traitsFor each pair of alternative traits, 1 was not expressed in F1 generation, but re-appeared in F2 generationTraits segregate among the progenyAlt, traits are expressed in 3:1 ratio in F2

11 Mendel proposed a simple model of heredity – 5 parts:Parents transmit “factors’ to offspringEach individual receives 2 factors which code for the same traitNot all factors are identical – alternative gene forms are called allelesAlleles do not influence each other as alleles separate independently into gametesThe presence of an allele does not insure that its trait will be expressed

13 Monohybrid CrossesPrinciple of Segregation – Mendel’s first Law of HeredityTwo alleles for a gene segregate during gamete formation and are rejoined at random, one from each parent, during fertilization.

14 Dihybrid CrossesDihybrid cross: examination of 2 separate traits in a single cross-for example: RR YY x rryyThe F1 generation of a dihybrid cross (RrYy) shows only the dominant phenotypes for each trait.

15 Dihybrid cross between two heterozygous parentsInstead of 4 possible outcomes, there are now 16!!

19 TestcrossTestcross: a cross used to determine the genotype of an individual with dominant phenotype-cross the individual with unknown genotype (e.g. P_) with a homozygous recessive (pp)-the phenotypic ratios among offspring are different, depending on the genotype of the unknown parent

About project

Feedback

To ensure the functioning of the site, we use cookies. We share information about your activities on the site with our partners and Google partners: social networks and companies engaged in advertising and web analytics. For more information, see the Privacy Policy and Google Privacy &amp Terms.
Your consent to our cookies if you continue to use this website.